After a user submits a search request to a search engine, the search engine retrieves a large amount of information that is relevant to the search request of the user. The search engine further orders the information based on a degree of relevancy between each piece of information and the search request to allow the user to quickly find his/her most desired information through the search engine.
Nowadays, search engines mostly use CTR (Click-Through-Rate) to reflect a degree of relevancy between each piece of information and a user's search request, where CTR is the quotient between a click rate and an exposure rate of the information. Upon computing the CTR of each piece of information, the search engine orders the information in a search result list in a descending order of the CTR.
During the study, inventors of this patent application, however, have noted that the degree of relevancy between a piece of information and a user search request is often related to the position of that piece of information in a search result list and the click sequence associated with the search result list. For example, CTR of information located in different positions may not be the same even though respective relevancies are the same in a same search result page. Alternatively, information that has been clicked by a user may influence the probability of clicking subsequent information.
Nevertheless, existing technology only considers click rates and exposure rates of information during the ranking process of search results, but fails to consider factors about positions of the information in the search result list and the click sequence associated with the search result list. As such, a relatively large variance exists in the relevancy scores used in the ranking process. In many cases, the information that a user desires is placed near the end of the search result list, leading to a poor search result ranking. On the other hand, when search results are poorly ranked, the user usually needs to browse and click on more information to obtain his/her most desired information. As the user “blindly” conducts extensive browsing and clicking in a website, workload of network systems, particularly, a server of the search engine, will be increased, thereby reducing the utilization rate of the network systems. The cost of the search process for the search engine server is therefore increased, wasting system resources of the search engine server.